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Finding the Fourth Proportional to 392.81, 542.06 and 215.78

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Solution

The fourth proportional to 392.81, 542.06 and 215.78 is: 297.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    392.81 : 542.06 = 215.78 : x
  2. Step 2: Convert to fraction form
    392.81/542.06 = 215.78/x
  3. Step 3: Cross multiply
    392.81x = 542.06 × 215.78
  4. Step 4: Simplify right side
    392.81x = 116,965.71
  5. Step 5: Solve for x
    x = 116,965.71/392.81
  6. Step 6: Final answer
    x = 297.77

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.